Static content gets downloaded even after expiry set to access + 1 month

[sachy78]

If I access my web application with primed cached then am able to only see dynamic hits. But when I close my browser and access the same application again, static as well as dynamic hits are made to the server. I am wondering why the static requests were made to server and not served from browser cache. Any help would be appreciated.
Following is my Apache settings and am using IE 7, Firefox 3.6.5 for my tests.

Header unset ETag
Header unset Last-Modified
FileETag None

ExpiresActive ON
ExpiresByType text/javascript "access plus 1 month"
ExpiresByType application/x-javascript "access plus 1 month"
ExpiresByType application/javascript "access plus 1 month"
ExpiresByType text/css "access plus 1 month"
ExpiresByType image/gif "access plus 1 month"
ExpiresByType image/png "access plus 1 month"
ExpiresByType image/jpeg "access plus 1 month"